One-component diazotype material



v diazo compound, and an organic':-acid.

Patented Jan. 9, 196 2 1 A 3,016,298 7 H Y ONE-COMPONENT DIAZOTYPE -MAIBRIAL .Theodorus Petrns Wilhelmus sua m' v smm nu} iiertus Wilhelmus Henrlcns Marla 'Roncken,-Roermond, Netherlands, assignors to Chemiscbe' ram-tar which tneutralize the acidapresent in 'the IigIitsensitive layer and enable the-formationof' themzoklyestufi. In the so-called semi-wet diazotype processdevelopmentis effected by coating the surfaceiof-theimagewiseexposed diazotype material evenly withla thin-layerof developing v United tes Pawnt Office,

:wetdevelopment of one-component diazotype material which has been sensitized with diazo compounds having a great coupling activity, such as p-diazo diphenylamine,

p-diazo o-chloro N-monocyclohexylaniline, p-diazo N.N-

' di-nQbutyI'aniIine, "p diazo N.N-di-n.-hexylaniline, p-diazo aniline,*p.diazo o chlo'ro N.N-diethylaniline, and certain p-diazo o'-alkoxy"'N.N dialkylanilines, such as p-diazo o 'e'thoiy Ni-N-di ni-propylaniline and p-diazo o-metho'xy -N-ethyl' -N-benz lanuine.

-Diazo compounds coupling even more actively than those just' referred *to'are' compounds such as 4 diazo 2,5'-dialko'xy a'cyltinilides, for example, 4-diazo 2,5-diethoityhe'nzanilide, 4-diazo 2,5-dialkoxy arylmercapto- "benzene compounds and 4-dia'zo 2,5-dialkoxy diphenyl *conipounds. 'Less "actively coupling diazo compounds are-compounds such as p-diazo N.N'-dimethylaniline, pdiazoNN-diethylanilinc, p-diazo m.methylN.N-dimethylaniline, and"diazo anhydrides such as Z-diazo-l-naphtholsulphonic"acid. On'a'ccount of their small coupling 'aetivity these actively couplingdiazo compounds are that suitedfor the'seini-wet development with the said developers reacting moderately alkaline. The coupling liquid of, forexam'ple, 8 g. per rn. developing;

- Iiquidmust'be able, in the short time in-which=a thin layer of'it dries up on'the surface of the diazotypematerial, to transform'essentially all the diazo-compound present'on the diazotype material intot'azo dye'stu'tl df the desired c'olour, in other words to;bringabout a*suhstantially complete development ofv thediazotype-tnaterial.

In this connection the coupling-activityefthe tiiazo compounds and a'zo couplingtcomp'onents used-"is 'na'turally of great importance. The conditions which are imp'orta'nt for substantially complete development always-have to' be adapted to the coupling activity of the diazo' e'ompounds and, 'azo coupling components used.- ln orde'r'to'obtain subsantially complete development, "the acid "content ot the light-sensitive layer and accordingly itspHand/or its buffer capacity, and/ or thepercentageof alkalis=and7 or 1 butler salts of the developing liquid and a'ccor'dingjly'the pH and/or the buffer capacity of that liquid, may. be varied in proportion to the coupling activity of the diazo compounds used for the sensitization of the one 'c'om t ponent' diazotype material. In prder'toniinimize or avoid deleterious effect on'the keeping quality attire-developed diazotype copy, on its mechanical strength, 'for 'ex'a'mple, its tearing-resistance, and on the fas'tness-rot the azo-dyestuif and of the background of-the copy, tor example, on exposureto light, and in order to maintain keeping quality, and freedom from crystallization, prevent v etching activity of the developing liquid, it'is endeavoured to keep-the acid content of the light-sensitivelayer and the percentage of alkalis or butter salts or the develop inglliquid at a low value.

activity: or thedittzo compounds can be determined com- 'paratively invitro'by measuring the time in which a I given portion (for'exarnple, 10%) of .the diazo com- ;pound 'to-be 'examinedwill have coupled in a given molar concentration (for example, 0.1 millimolar) with the couplingconipone'nt l-ph'enyI S-methyl pyrazolon'e-(S) in a"given molarco'ncentration (for example, 1.0 ,milliniolaryin shutter mixture of a given composition and agivenipl'l at'a given temperature.

-Dia'z'otype materials sensitized'withthe above-mentioned very actively coupling diazo compounds of the groups of 4-diazo 2,5-dialk'oity acylanilide, 4-diazo 2,5-dialkoxyarylmercaptobe'nze'ne', 4-diazo 2,5-dialkoxydiphenyl, as

far as-their' coupling'activity is concerned are suited for semi-wet development with 'very weakly alkaline, neutral or even weakly acidicbut strongly buttered developers. With such developers'co'ntaining phloroglucinol they are able'tos'give fine'bla'ck a'z o-d'ycstuils. With the said developers reacting moderately alkaline, however, they yield i-azo'edyest uflswith less pure (or less neutral) shades,

. ing' the rnoderately' alkaline reaction .of the developing Developers reacting moderately alkaline are therefore preferredto those reacting strongly alkaline, and developerswith a low percentage of huti'ersalts to those with ahighfpercentage of butler salts. A developing liquid reacting moderately alkaline has a pH between 8 and 11 and contains alkali salts, such as bonus, car'- bonates, and phosphates. The couplingcomponent it contains is generally phloroglucin'ol, a very actively coupling compound, which is able to'couple at one, two" or three places with the'diazo compound and in proportion thereto forms deystutfs of various shades. p

In order to obtain certain neutral shades, use is also made of a mixture of phloroglucinol with other coupling components, for "example, vresorcinol.

With such developers reacting'moderately alkaline substantially complete development is'acliieved the semirgenerally lighter coloured, for example, brownish or purplieih shades of colour, because during development the pll'oithe surface of thediaz'otype material, notwithstandliquid, is's'till too high in relation to the very great cou- .pli'ngactivity of the diazo compounds. This is. called over-development.

Etforts have been made to manufacture with the said very actively coupling diazo compounds diazotype materia'lswhich are suitedtor semi we't development with the said developers reacting moderately alkaline, and

which in this process will not be over-developed,,but give pure or neutral) a'z'odyestufl:' shades. For this purthe light-sensitive layer of these diazotype materials has been given a high content of acid. Whilst the sensitizing liquids for the manufacture of diazotype" material's-with thesefdiazo compounds usually contain only approximately 05-1 of their weight of the acids normally used in one-component diazotype layers, such as tartaric acid, citric acid, aluminum sulphate, alum, and the'like, and the diazotype materials produced therewith 1 are; then suited for semi-wet development with weakly I alkaline to weakly acidic buttered developers, they have l to contain about 3 to 4% of these acids for the manufacture of diazotype materials which are suited for the.

semi 'wet development with the above-mentioned developera reacting moderately alkaline.

- Though the butierin'g capacity of the light-sensitive layer of one-component diazotype materials which contain so large a quantity of such an acid is higher than that of the corresponding-materialscontaining a small amount of acid, it is nevertheless insuflielent for the practice of the semi-wet diazotype process with the said developers reacting'm ofclrately alkaline. In fact, the materials, are verysensitive to development fluctuations when such" developers containing polyvalent azo coupling components, such as phloroglucinol, are used. These fluctuations generally arise because the quantityof developer applied itself fluctuates, for example, owing to shocks or vibrations of the developing apparatus or when its speed is changed. Other causes may be a change in the concentration of the developers, for example, through a mistake in the preparation .of the solution or owing to evaporation of the latter during use or slight irregularities in the light-sensitive layer owing to which it does not take up the developer quite uniformly. In current practice development fluctuations now occur to a greater extent fisince formerly a large excess of dilute developer was used whereas in the modern semi-Wet diazotype process the quantity of developer applied per unit-surface, which developer is generally used in a more concentrated form,

- is kept small. The sensitivity of the light-sensitive layer to development fluctuations is shown by shifts in shades in the colours of the image, for example, by deviations from the desired neutral black. If, for example, a neutral black colour is obtained with a developer of the correct concentration containing phloroglucinol, a violetblack shade is obtained with a developer which contains only 80% of the usual quantity of water or has been evaporated to this value, whilst with a developer which is too dilute a'green-black shade is obtained and often not all of thediazo compound is converted into azo-dyestuff. Diazotype material, especially diazotype paper, which contains suchlarge quantities of the said fairly strong acids, upon ageing also shows a considerable decrease of its 1 mechanical strength, which appears, for example, from a reduced tearing-resistance.

In order to avoid the objectionable consequences of development fluctuations in the semi-wet development of diazo film layers, it has been proposed to sensitize diazo film layers with a p-diazo-dialkylaminobenzene compound each-alkyl group of which .containsat least 4 and 'at most 7 C-atoms, while both alkyl groups contain together 10, 11 or 12 C-atoms and at most one of the two alkyl, groups carries a side-chain attached to the a-C- atom. These diazo compounds couple actively and the diazo film layers sensitized with them are suited for the semi-wet development with the said developers reacting moderately alkaline. These diazo film layers contain very small quantities of the acids normally used in the diazotype process, such as tartaric acid, citric acid, and alum.

Besides tartaric acid and citric acid, other organic acids or their salts have also been applied inthe lightsensitive layer of diazotype" materials.

Thus, a process is known for deepening the shades of colour when one-component diazotype material which has been sensitized with p-amino-benzene diazo compounds is used. In this process an unsaturated organic compound with one or more carbon double bonds, for example, the sodium salt of maleic acid, itaconic acid or citraconic acid,- is used' in the light-sensitive layer or compounds. Even upon application of free itaconic. acid,

the keeping quality of such material is very poor. Moreover, itaconic acid and citraconic acid are rather expensive.

It has further been proposed to manufacture lightsensitive layers with the aid of reaction products of diazoanhydrides with salts of organic aliphatic or aromatic acids, such as acetic acid, lactic acid, tartaric acid, citric acid, oxalic acid, succinic acid, benzoic acid, and benzene sulphonic acid. Such layers naturally contain only a small quantity of an acid combined with the diazo molecule. The coupling activity of diazo-anhydrides is very low, so that they are not suitable for application in one-component diazotype material for the semi-wet diazotype process with a developer reacting moderately alkaline.

According to the present invention a one-component diazotype material has a light-sensitive layer which contains a diazo compound coupling at least as actively as p-diazo diphenylamine, preferably a diazo compound that can readily couple with phloroglucinol in an acid mediumand an aliphatic saturated dicarboxylic acid in which the carboxylic acid groups are linked with two carbon atoms which form part of a hydrocarbon radical that may or may not be substituted and which has 2 to 8 carbon atoms, which acid has electrolytic dissociation constants smaller than 2.3 X 10- the said light-sensitive layer containing a quantity of said acid equimolarly corresponding to at least 0.20 g. of succinic acid per m of its lightsensitive surface. Semi-wet development of said diazotype material with the usual developers reacting moderately alkaline yields azo-dyestuffs with attractive pure (and neutral) shades ofcolour. Fluctuations in the application or concentration of the developer have a much smaller influence on the shade of the azo-dyestuifs when diazotype material according to the invention is used than if use is made of similar diazotype materials containing the usual acids, such as citric acid and tartaric acid. Upon ageing, diazotype material according to the invention furthere shows less loss of its mechanical strength. By the useof one-component diazotype material according to the invention'it is possible to achieve, with one and the same developer reacting moderately alkaline,.a substantially complete development-which is only slightly affected, if at,all, by development fluctuations-both of transparent diazotype material sensitized with actively coupling diazo compounds which upon semi-wet development give azo-dyestufls with a high absorption for ultraviolet light, such as p-diazo o-chloro N.N-d iethylanilinc, and of diazotype material sensitized with very actively coupling diazo compounds, such as 4-diazo 2,5-dialkoxy acylanilides, 4-diazo 2,5-dlalkoxy arylmercaptobenzene compounds, and 4-diazo 2,5-dialkoxy diphcnyl compounds;

With the azo coupling components normally used in the semi-wet diazotype process, for example, with phloroglucinol and resorcinol, the very actively coupling con1- pounds of the said groups yield azo-dyestutls which are highly resistant to oxidation and to the action of light. Moreover, the photo-decomposition products which remain in the exposed portions of the diazotype copy afterthe imagewise exposure of the diazotype material sensi-- tized with these very actively coupling diazo compoundsare highly resistant to oxidation or to the action of light. The azo-dyestufls of the said very actively coupling diazocompounds do not, however, have high absorption for ultra-violet light, so that these diazo compounds are not particularly suited for the sensitization of transparent diazotype materials which are used for the production of intermediate copies. However, there are other actively coupling compounds, such as p-diazo o-chloro N.N-diethylaniline and p-diazo o-methyl N.N-diethylariilinc, which with phloroglucinol and resorcinol yield a'zo-dyestuffs which possess very high absorption for ultra-violet light and which are therefore very suitable for the manufacture of transparent diazotype material. Such transparent material is not suited for semi-wet development with weakly alkaline to weakly acidic buffered developers, because during development the pH of the surface of the diazotype material is still too low in relation to the coupling activity of the diazo compound, though this activity acumen is large. The diazo compound is not completely converted into azo-dyestulf. This is called underdevelopment. Said transparent diazoty'pe' materials are, however, well suited for semi-wet development with the said developers reacting moderately alkaline.

In practice transparent and non-transparent diazotype materials are preferably developed with one and the same developer.

The acids included in the diazotype material according to the invention are in general readily available. Those as methyl alcohol, ethyl alcohol, acetone, and the like.

The diiferences'between the two dissociation constants of the said aliphatic saturated dicarboxylic acids are con siderably smaller than those present in other organic dior tricarboxyli'c acids, such as oxalic acid, tartaric acid, citric acid ormaleic acid. The last-mentioned acids have a-first electrolytic dissociation constant which is considerably greater than 23x10". The hydrocarbon radical with which the two carboxylic acid groupsin the acids applied'in the diazotype material according to' the invention, are linked may or may not be branched; it is also possible for one or more hydrogen atoms of the hydrocarbon radical to be replaced by groups other than carboxylic acid groups, for example, by amino-, mono-, and dialkylamino groups; the carboxylic acid groups may be linked with two adjacent carbon atoms or with two carbon atoms which are further apart. Suitable acids are, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, az elaic acid, sebacic aid, anti-dimethyl succinic acid, ethyl-succinic acid, fi,B-di1nethyl glutaric acid,

ti-methyl adipic, acid, aspartic acid and glutamic a'cid The acid content of thelight-sensitivelayer of onecomponent diaz'otype material according to the invention may vary according to the variation of the diazo content.

In order to avoid the objectionableconsequences of development fluctuations, however, a relatively high acid content of the light-sensitive layer of the one-component diazotype material is always needed.

Th acid contentinay be relatively larger as the coupling activity of the diazo compounds used is greater. In order to .achievesubstantially complete deyelo'pment rof one-component diazotype material containing only the usual acids, such as citric acid and tartaric acid, a precise quantity of these acids is necessary when a given developer reacting moderately alkaline is used. A small excess of the acids 'causes under-development, a small shortage of the acids causes over-development. The acid content of the one-component diazotype material according to the invention may vary within much wider limits without causingoveror under-development.

For the manufacture of one-component diazotype material according to the invention it is not necessary to replace the quantity of citric acidfor other conventional acid in a given one-component diazotype material by'an equivalent quantity of acid according to the invention. It is possible to use considerably more than theequivalent quantity of the last-mentioned acid. I The larger the quantity-of this acid that can be applied, the better' can the detrimental consequences of development fluctuations be avoided, while the drawbacks involved in a high acid content of the light-sensitive layer do not appear or, in a much lower degree, than if use is made of a similar diazotype material with a high content of a conventional acid, such as citric acid or tartaric acid.

- As appears from the above description, there are diffcrences in coupling activity between the actively coupling diazo compounds suitable for application in onecomponent diazotype material according to the invention. The avoidance ofthe detrimental consequences of development fluctuations in general is greatest upon the use of diazo compounds with the greatest coupling activity. Very good results are obtained with one-component diazotype material according to, the invention in which the actively coupling di'azo compound is a compound of the type:

in which X is an anion and R an alkyl or aralkyl group. The acyl group may be, for example, acetyl, propionyl, benzoyl, p-chloro-benzoyl, phenyl-acetyl or phenoxy'acetyl. A familiar compound of this type is, for example, the 4-benzoylamino 2,5-diethoxybenzene diazonium chloride, zinc chloride double salt.

Good results are also obtained with One-component diaptypematerial according to the invention in which the actively coupling dianocompound is a compound of the type: I i

In another favourable one-component diazotype material according to the invention the actively coupling diazo compound is a compoundof the type in which X is an anion, R an alkyl or aralkyl group, and R anarylgroup that may or may not be substituted. A-suitable compound of this type is, for example, 1-

' f' dia'zo 2,5-diethoxy-4@methoxydiphenyl.

- such as caffeine, theobromine or theophylline.

Attractive black azo-dyes tutt images can thus be obtained with one-component diazotype material according to the invention the light-sensitive layer of which con- -tains a xanthine.

The diazotype material according to the invention may contain the auxiliary substances commonly used in onecomponent diazotype materials, for example, means preventing the discoloration of diazotype copies, such as thiourea, constituents facilitating the sensitization, such as gelatin, gum arabic and isopropyl alcohol; substances which prevent curling, such as glycerol and polyethylene glycol; means promoting the uniformity of the light-sensitive layer, such as dispersions of silica, aluminium oxide, titanium dioxide, barium sulphate, synthetic resins and unboiled starches such as rice starch; means preventing ink-feathering in writing or drawing on copies on such.

material. such as water-soluble salts of sym. diaryl- 7 guanidines, for example, sym. diphenylguanidine', stabilizers, for example, acids oracid salts such as citric acid, tartaric acid, alum and 1.3.6-naphtalene trisulphonic acid. However, no large quantities of the said acids or acid salts must be used, since otherwise no substantially complete development will be achieved with developers reacting moderately alkaline.

' An excellent keeping quality is shown by one-component diazotype material' according to the invention the light-sensitive layer of which contains a mixture of boric acid and an organic hydroxy acid capable of forming a complex with boric acid. A small quantity of a mixture of boric acid and tartaric acid or boric acidand citric acid sufiicient.

The following examples will serve to illustrate the invention:

' Example I I White base-paper for the diazotype process of weight 80 g ./m. is sensitized with a solution of:

20 g. of p-4-methyl phenylmercapto-2,S-dimethoxybenzene diazonium chloride, zinc chloride double salt 50 g. of succinic acid 2 g. of thiourea 35 g. of rice starch 30, cn- 1. of a dispersion of polyvinylacetate (Vinnapas 1000 cm. of water and dried.

The sensitized surface contains approximately 0.2 g. of

the diazo compound and approximately 0.5 g. of succinic acid per m. Under a transparent original drawn in pencil a sheet of the diazotype paper is exposed in an exposure apparatus'equipped with a high-pressure mercury vapour lamp until the portions of the light-sensitive layer lying under the transparent portions of the original are substantially (not completely) bleached, as is customary in practice when making copies of pencil-drawings. The

' imagewise exposed sheet is developed by applyingapproximately 8 -g./m. of the following developing liquid:

This developing liquid has a pH of 9.4. The developed copy shows a strong black posifiv image on a foggy background. If the concentration of the constituents of this developer has increased, for example, in consequence of evaporation of the developer in the developing apparatus, to such an extent that the original volume of 1050 cm. has decreased to about 700 cm. upon development of a copy'on this light-sensitive material in an otherwise similar way an image is obtained of which the shade of the azo-dyestuif does not deviate substantially from that of the image obtained with the normally concentrated developer.

If, instead of 50 g. of succinic acid, 40 g. of citric acid or 45 g. of tartaric acid or 30 g. of maleic acid is used in the sensitizing liquid, a substantially complete development is indeed obtained with the above-mentioned normally concentrated developer, but with the developer evaporated to 700 cm. a brown-violet instead of a. black azo-dyestufi shade is obtained.

8 Example II White base-paper for the diazotype process of weight 80 g./m. is sensitized with a solution of:

20 g. of p-4'-methoxy phenyl 2,5-diethoxybenzene diazonium chloride, zinc chloride double salt 45 g. of glutaric acid 1 g. of gelatin in 1000 cm! of water and dried.

The sensitized surface contains approximately 0.21 g. of the diazo compound and approximately 0.45 g. of glutaric acid per m A sheet of the diazotype paper is imagewise described in Example I.

The imagewise exposed sheet is developed by applying approximately 8 g./m. of the following developing liquid:

26 g. of thiourea 6.5 g. of phloroglucinol 6.5 g. or resorcinol' 1.5 g. of Sorbit P 3 g. of sodium salt of ethylene diamine tetra-acetic acid 32 g. of sodium carbonate 1000 cm. of water This developing liquid has a pH of 9.5.

The developed copy shows a strong black positive image on a foggy background with little variation of shade in consequence of development fluctuations. If, instead of 45 g. of glutaric acid, 33 g. of ortho-phosphoric acid or 50 g. of alum or 40 g. of aluminium sulphate is used exposed as in the sensitizing liquid, considerable variations in azodyestufi shade owing to development fluctuations are obtained.

Example III White base-paper for the-diazotype process of weight 80 g./m.= is sensitized with a solution of:

Example IV Paper of weight g./m. one side of which has been coated with a cellulose acetate layer (approximately 50% by weight of combined acetic acid) with a thickness of about 10 microns, which has been fixed to the paper by means of an adhesive and which has been deacylated to a depth of about 4 microns and to an average acetyl content, calculated as combined acetic acid, of approximately 20% by weight (which corresponds to an average number of acyl groups linked with the OH-groups of 0.7), is impregnated on the deacylated side of the cellulose acetate layer during 30 seconds with the following solution:

65 g. of p-4-methyl phenylmercapto 2,5-diethoxy benzene diazoniurn chloride, zinc chloride double salt 2 g. of alum 300 cm. of ethyl alcohol (96%) in 700 cm. of water dried, treated further with a solution of:

75 g. of suberic acid in 1000 cm. of ethyl alcohol (96%) and dried again.

6.5 g. of phloroglucinol Before drying, the excess of liquidis removed each time from the cellulose acetate surface. The sensitized surface contains approximately 0.28 g. of the diazo' compound and approximately 0.9 g. of s'ubcric acid per m. A sheet of the diazotype paper is exposed under a transparent original drawn in ink until the ortions of the light- -sensitive layer lying under the transparent portions" of the original are completely bleached out.v The imagewis'e 1000 cm. of water The developing liquid has a pH of 9.4. I v

The developed copy shows a strong black positive image on a bright white backgro'ri'nd with few deviations in shade, if any, in consequence of vibrations and mechanical irregularities of the developing apparatus.

If the light-sensitive surface contains 0.42 g. of citric acid instead of 0.9 g. of suberic acid, considerable difierences in-a zo-dyestufl shades are obtained in consequence of vibrations and mechanical irregularities of the developing apparatus, for example, in the form of alternating green-black, black, and brown-black streaks in the azodyestuff image. I v Example V White base-paper for the diazotype process; of weight 80 g./m. is pre-coated with approximately g'Jin. of an aqueous polymeric methacrylic acid ester dispersion diluted withwater in a proportion of l to 5 parts of water, in whi ch0.l% by weight of Tylose SL has been dissolved.

It is dried in a current of air at 100 C. The surface thus treated is sensitized with a solution of:

15 g. of p-4-methyl phenyl-mercapto 2,5-diethoxy-benzene diazonium chloride, zinc chloride double salt 5 g. of p-benzoylamido 2,5-diethoxy benzene diazonium chloride, zinc chloride double salt g. of succinic acid 12 g. of adipic acid 2 g. of boric acid 5 g. of tartaric acid 2 g. of thiourea 10 g. of cafieine 2.5 g. of gelatin in 1000 cmfiiof water and dried.

The sensitized surface contains about 0.15 g. of themercapto-diazo compound, about-0.05 g. of the acylamido diazo compound, about 0.4 g. of succinic acid and about 0.12 g. of adipic acid per m. I II I A sheet of thediazotype paper is exposed and developed as described in Example I. I I II I I ,I I

The developed copy shows a strong black image on a foggy background with little variation of shade in consequence, of development fluctuations.

Example VI White base-paper for the diazotype process of 80 g./m. is sensitized with a solution of: I 23 g. of p4'-methyl phenylnaei'capto as-dreamy benzene diazonium chloride, zinc chloride double salt weight .20 g. of caffeine 30 g. of succinic acid cinic acid per m 10 20 cm. of a dispersion of polyvinyl acetate (Rhodopa 6000) in 1000 cm. of water and dried.

The sensitized surface contains approximately 0.2 g. of the diazo compound and approximately 0.26 g. of suc- A sheet of the diazotype paper is irnagewise exposed as described in Example I.

The imagew'ise exposed sheet is developed by applying approximately 8 gJm. of the following developing liquid:

6.5 g. or hiorogrucmor 6.5 g. of resorcinol '1' g. of potassium 's'alt of'hydroquinone monosulphonic acid 1.5 g. of Sorbit P I 10 g. of beet sugar g. of potassium tetraborate pentahydrate 20 g. of benzoic acid 1000' cm. of water The developing liquid has a pH of 8.4.

in which X is an anion, R is a radical selected from the group consisting of alkyl and aralkyl radicals, and Y is a radical selected from the group consisting of acylamino, arylmerca'pto, and aryl radicals, and containing with said compound an aliphatic saturated dicarboxylic acid in which the carb'oxylic acid radicals are linked with two carbon atoms forming part of a hydrocarbon radical having from 2 to 8 carbon atoms, the electrolytic dissociation constants of said acid being smaller than 2.3 X10 said composition providing at least 1.7 millimols of said acid per'square' meter of the area of said side.

2. A one-component diazotype material comprising paper having a fibrous side thereof sensitized by a lightsensitive composition containing, and in the absence of an 2120 coupling component, an actively coupling lightsensitive diazo compound of the formula of said side.

3. A one-component diazotype material comprising paper having a fibrous side thereof sensitized by a light- .sensitive composition containing, and in the absence of an azo coupling component, an actively coupling lightsensitive diazo compound of the formula XN SRi in which X isan anion, R is a radical selected from the group consisting of alkyl and aralkyl radicals and R is an aryl radical, and containing with said compound an aliphatic saturated dicarboxylic acid in which the carboxylic acid radicals are linked with two carbon atoms forming part of a hydrocarbon radical having from 2 to 8 carbon atoms, the electrolytic dissociation constants of said acid being smaller than 2.3x said composition providing at least 1.7 millimols of said acid per square meter of the area of said side.

4. A one-component diazotype material comprising paper having a fibrous side thereof sensitized by a lightsensitive composition containing, and in the absence of an azo coupling component, an actively coupling light-sensitive diazo compound of the formula in which X is an anion, R is a radical selected from the group consisting of alkyl and aralkyl radicals and R is an aryl radical, and containing with said compound an aliphatic saturated dicarboxylic acid in which the carin which X is an anion, R is a radical selected from the group consisting of alkyl and aralkyl radicals, and Y is a radical selected from the group consisting of acylamino, arylmercapto, and aryl radicals, and containing with said compound an aliphatic saturated dicarboxylic acid in which the carboxylic acid radicals are linked with two carbon atoms forming part of a hydrocarbon radical having from-2 to 8 carbon atoms,-the electrolytic dissociation constants of said acidbeing smaller than 2.3X10' said composition providing at least 1.7 millimols of said acid per square meter of the area of said side, said composition also containing a xanthine.-

' 6. A one-component diazotype material comprising paper having a fibrous side thereof sensitized by a lightsensitive composition containing, and in the absence of aniazo coupling component, an actively coupling lightsensitive diazo compound of the formula in which X is an anion, R is a radical selected from the group consisting of alkyl and aralkyl radicals and R is an aryl radical, and containing with said compound an aliphatic saturated dicarboxylic acid in which the carbon- 7. A one-component diazotype material comprising paper having a fibrous side thereof sensitized by a lightsensitive composition containing, and in the absence of an azo coupling compound, an actively coupling lightsensitive diazo compound of the formula in which X is an anion, R is a radical selected from the group consisting of alkyl and aralkyl radicals and R is an aryl radical, and containing with said compound an aliphatic'saturated dicarboxylic acid in which the carboxylic acid radicals are linked with two carbon atoms forming part of a hydrocarbon radical having from 2 to 8 carbon atoms, the electrolytic dissociation constants of said acid being smaller than 2.3x 10*, said composition providing at least 1.7 millimols of said acid per square meter of the area of saidside, said composition also containing a xanthine.

8. A one-component diazotype material comprising paper having a'fibrous side thereof sensitized by a lightsensitivecomposition containing, and in the absence of an azo coupling component, an actively coupling light-sensitive diazo compound of the formula in which X is an anion, R is a radical selected from the group consisting of alkyl and aralkyl radicals, and Y is a radical selected from the group consisting of acylamino, arylmercapto, and aryl radicals, and containing with said compound an aliphatic saturated dicarboxylic acid in which the carboxylic acid radicals are linked with two carbon atoms forming part of a hydrocarbon radical having from 2 to 8 carbon atoms, the electrolytic dissociation constants of said acid being smaller than 2.3 X 10- said composition providing at least 1.7 millimols of said acid persquare meter of the area of said side, said composition also containing boric acid and an organic hydroxy compound capable of forming a complex with boric acid.

9. A one-component diazotype material comprising paper having a fibrous side thereof sensitized by a lightsensitive composition containing, and in the absence of an azo coupling component, an actively coupling lightsensitlve diazo compound of the formula in which X is an anion, R is a radical selected from the group consisting of alkyl and aralkyl radicals and R is an aryl radical, and containing with said compound an aliphatic saturated dicarboxylic acid in which the carboxylic acid radicals are linked with two carbon atoms forming part of a hydrocarbon radical having from 2 13 10. A one-component diazotype material comprising paper having a fibrous side thereof sensitized by a lightsensitive composition containing, and in the absence of an azo coupling component, an. actively coupling lightsensitive diazo compound of the formula xm-QR,

I in which X is an anion, R is a radical selected from the group consisting of alkyl and aralkyl radicals and R, is an aryl radical, and containing with said compound an aliphatic saturated dicarboxylic acid in which the carboxylic acid radicals are linked with .two carbon atoms forming part of a hydrocarbon radical having from 2 to 8 carbon atoms, the electrolytic dissociation constants of said acid being smaller than 2.3X10 said composition providing at least 1.7 millimols of said acid per square meter of the area of said side, said composition also containing boric acid and an organic hydroxy compound capable of forming a complex with boric acid.

11. A one-component diazotype material comprising paper having a fibrous side thereof sensitized by a lightsensitive composition containing, and in the absence of an azo coupling component, an actively coupling lightsensitive diazo compound of the formula KN,- Y

i in which X is an anion, R is a radical selected from the group consisting of alkyl and aralkyl'radicals, and Y is aradical selected from the group consisting of'acylamino, arylmercapto, and aryl radicals, and containing with said compound an aliphatic saturated dicarboxylic acid in which the carboxylic acid radicals are linked with two carbon atoms forming partof a hydrocarbon radical hav- 14 an azo coupling component, an actively coupling light sensitive diazo compound of the formula v :(N s-Ri in which X is an anion, R is a radical selected from the group consisting ofaikyl and aralkyl radicals and R is an aryl radical, and containing with said compound an aliphatic saturated dicarboxylic acid in which the "carboxylic acid radicals are linked with two carbon atoms forming part of a hydrocarbon radical having from 2 to 8 carbon atoms, the electrolytic dissociation constants of said acid being smaller than 2.3 10-*, said composition providing at least 1.7 millimols of said acid per square meter of the area of said side, said composition also containing a xanthine and boric acid and an organic hydroxy compound. capable of forming a complex with boric acid.

13. A one-component diazotype material comprising paper having a fibrous side thereof sensitized by a lightsensitive composition, containing, and in the absence of an azo coupling component, an actively couplingliightsensitive diam compound of the formula XN R1 a in which X is an anion, R is a radical selected from the .group consisting of alkyl and aralkyl radicals and R,

i meter of the area of said side, said composition also conis an aryl radical, and containing with said compound an aliphatic saturated dicarboxylic acid in which the carboxylic acid radicals are linked with two carbon atoms forming part of a hydrocarbon radical having from 2 to 8 carbon atoms, theelectrolytic dissociation constants of said acid being smaller than 2.3 X 10-, said composition providing at least 1.7 millimols of said acid per square taining a xanthine and boric acid and an organic hydroxy compound'capaible of forming a complex with boric acid.

References Cited in the file of this patent UNITED STATES PATENTS 1,870,930 Spongerts Aug. 9, 1932 2,405,523 Sease et at. Aug. 6 1946 FOREIGN PATENTS 415,081 Great Britain Aug. 16, 1934 

1. A ONE-COMPONENT DIAZOTYPE MATERIAL COMPRISING PAPER HAVING A FIBROUS SIDE THEREOF SENSITIZED BY A LIGHTSENSITIVE COMPOSITION CONTAINING, AND IN THE ABSENCE OF AN AZO COUPLING COMPONENT, AN ACTIVELY COUPLING LIGHTSENSITIVE DIAZO COMPOUND OF THE FORMULA 